We propose to develop an adequate conceptual and physical experimental model to examine the interaction between sensory and emotional components of pain, and to relate experimental pain to clinical pain. For the study of experimental pain, thermal stimuli, continuous electrically induced pain and ischemic pain by tourniquet will be used. Data derived from these models will serve to correlate with "titration" studies of thermal stimuli superimposed in chronic patients with comparable pain. The aim is to develop means to quantify clinical pain by experimental pain and questionnaires.